Speedometer works after driving X miles?

[jlynch1960]

My speedometer sometimes doesn't kick in until the car's been driven for a while (5-20 miles or so), then it jumps into place and works fine. Seems to have something to do with the car being warmed up - works again with warm starts. Only happens after car's been sitting a couple of days. Sometimes it works fine on cold starts too. Did a search, but no answer. 84 Carrera. Sending unit? Corrosion in the unit? Had it apart for odometer gear fix and it looks okay.

[DRACO A5OG]

well it canbe several areas

1. check the sensor at the trans, it is basically a magnet, remove from trans and turn the car to on position, engine off and pass a metal tool over it to see if it bounces the needle.

2. check that the tunnel at the coupler area to insure the oonnection is nice and seated all the way in, wouldn't hurt to clean it as well.

3. the gauge, insure the ground is clean and tight. check all connections as well.

if all checks out, then it could be a loose solder within the gauge, especially the green signal wire. from what you describe when she is cold, the fractured solder will have little or no continuity, when it warms up the rakee solder will expand and make enough contact to work. hope this makes sense.

Jim

[jlynch1960]

Yeah, thanks it does make sense. Need to take it apart again to replace odo gear and will check the solder. I'll have a look at the other areas as well. Thanks again.

[Wei2go]

Did you find where's the problem? I have exactly the same problem...